Research On Robust Control And Filtering Methods Of Networked Systems Based On Different Communication Mechanisms

Exploring the networked and digitized needs of oil and gas fields,and promoting the deep fusion of information and communication technology,automatic control technology and oil and gas industry,the digital oilfield construction has been a future development trend which aims to realize green,intelligent,energy-saving,safe and efficient.Petroleum production process under network environment,network induced phenomena such as delay,packet loss and quantization error are inevitably introduced in transmitting or exchanging data information due to each intelligent node shares the communication channel with limited bandwidth,which makes the performance of the systems decline,and brings greater difficulties and challenges to the control/filtering.And moreover,as the gradual expansion of industrial production scale and the gradual increase of the number of access network nodes,the reliability of data transmission and the limited communication resources during petroleum production have become increasingly prominent.Therefore,the stability,security and energy saving of the systems are the basic requirements for advocating the digital oilfield construction.The topic of this paper directly faces the dependence between the uncertainty of network induced phenomenon,limited communication resources and the performance of industrial systems,according to the requirements of system restraining strong noise,maintaining performance and saving communication resources,the robust control/filtering research which satisfies different performance requirements is carried out by using Lyapunov stability theory and techniques such as linear matrix inequality based on different communication mechanisms.The main research content of this paper is divided into three parts:In the first part,from the perspective of data transmission reliability and performance of petroleum production systems,the control/filtering problems are discussed for the networked systems based on the time triggering communication mechanism.In Chapter 2,the time varying delays in data transmission are modeled as a random sequence satisfying a Bernoulli distribution,and the observer and controller design are investigated for networked switched systems with random delays and uncertainties under the constraints of H_∞performance index.Furthermore,the proposed design method is applied to the dynamic positioning system of the offshore drilling platform to test the practical application value of the proposed theoretical research method in the petroleum industry.Then,considering the effects of the delay,packet loss and quantization error on networked nonlinear stochastic systems in Chapter 3,stability and L₁performance criterion are proposed by exploiting the delay-dependent and fuzzy basis-dependent Lyapunov-Krasovskii functional,the It?o stochastic differential equations and the Newton-Leibniz formulas,and effective controllers and filters are further designed.In the second part,on the basis of the event triggering communication mechanism,the control/filtering problems are studied for networked uncertain systems,which intents to realize the energy saving and consumption reduction,stable and reliable operation and increasing benefits in the oil production process under communication constraints.In Chapter4,parameter design methods of controller and filter are discussed for a class of networked uncertain systems sustain persistent strong noise interference and fault constraints on account of linear matrix inequalities.Moreover,the theoretical research result is used for the free-water dehydrating system model of oilfield combined station to estimate the oil-water interface and pressure,which provides a certain reference value for practical industrial application.At last,aiming at the problems of saving communication resources,network induced delay,switching mode identification delay and switching signal design for networked switched LPV systems,the design method of asynchronous filter is given in Chapter 5 with mode dependent average dwell time,and the parallel result of synchronous switching is obtained.The third part sublimates the research results of the first and the second parts.On the premise of comprehensively considering network service quality and system performance,the design of the L₁fault detection filter is discussed for a class of networked nonlinear control systems by exploring the hybrid time/event triggering communication mechanism,which devotes to save energy,increase efficiency and promote the sustainable development of the petroleum industry.Finally,the proposed fault detection filter is applied to the motor model for pumping well,which verifies the effectiveness of the method by a simulation and provides guarantee for operation of the oilfield production safety and stability.The hybrid time/event triggering communication mechanism discussed in this part is a frontier topic in the field of networked nonlinear systems,which broadens the solution of system performance and energy efficiency concerned by networked industrial control systems,and provides a theoretical reference for engineering practice.